The dean encouraged Prince Philip to chair the annual St George’s House Lecture, which was once addressed by the Princess Royal. Their correspondence began when, in 1982, Prince Philip sent Michael Mann a copy of astronomer Sir Fred Hoyle’s lecture on evolution from space, in which he challenged parts of Darwin’s theory of evolution. There followed a lively debate back and forth, with Philip taking a more scientific stance against Mann’s theological viewpoint.

Philip expressed the view that ‘the point of life is to attempt to make it more tolerable and more civilised for the generations we have every reason to believe will live after us’. The dean saw life as a stepping stone to afterlife. He said: ‘Heaven is not necessarily guaranteed. It will matter how you have lived this life.’ In subsequent correspondence, Philip went on to write about what he described as his hobby-horse – the need to reconcile science and theology. ‘I don’t think the Church can hope to regain the ability to bring the influence of Christian principles to bear on the formation of opinion and intellectual fashion until the conflict between science and theology has been resolved,’ he wrote.

Mann was opposed to the publication of their correspondence, but Philip consulted the Queen, who encouraged it because it showed Philip in a good light as someone who is interested in religion and philosophy.

It would have been impossible to live with someone like Prince Philip without being influenced by his thoughts and beliefs, and of course the Queen has been. Prince Philip has an enquiring mind and if he had a motto it would be ‘never give up’. Although the Queen has adopted many of his opinions, she interprets them in a gentler, more understanding way, especially when it comes to their children.

When Lord Mountbatten was killed by an IRA bomb on 27 August 1979, together with his fourteen-year-old grandson Timothy Knatchbull, Prince Charles was devastated. ‘I have lost someone infinitely special in my life,’ he wrote later, but he never sought comfort from his father. Instead, he turned away from him. When the two of them were due to receive Lord Mountbatten’s body from Lydd airport on its way back from Ireland, Philip was at his worst. He masked his own grief with a brusque and abrupt manner, while Charles retreated into himself.